What you have is a customized "big truck" bumper. I think these were a heavy duty option on the big trucks (1-1/2 ton and larger) because I've also seen big trucks with the smaller chromed bumper like the 1/2 tons. The piece of sheet metal on the top was added by a previous owner and is not part of the original design. Here's a shot of one in it's stock form:
http://www.stovebolt.com/gallery/petra_daniel_1942.htm --Bob
